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Published on: July 11, 2015
Enhancing bactericidal activity of bovine lymphoid cells during the periparturient period
K A Shafer-Weaver1, L M Sordillo
1Department of Veterinary Science, Pennsylvania State University, University Park 16802, USA.
Insights
Bovine lymphocytes stimulated with interleukin-2 showed enhanced antibacterial activity against Staphylococcus aureus. This suggests a potential in vivo mechanism to boost mammary gland resistance during infection susceptibility.
Area of Science:
- Veterinary Immunology
- Bacterial Pathogenesis
- Cellular Immunology
Background:
- Bovine lymphocytes play a crucial role in immune responses.
- Mammary gland infections, such as mastitis, pose significant economic challenges in dairy farming.
- Understanding lymphocyte-mediated antibacterial mechanisms is vital for improving herd health.
Purpose of the Study:
- To investigate the in vitro antibacterial activity of bovine lymphocytes stimulated with interleukin-2 (IL-2).
- To identify the cellular phenotype responsible for this antibacterial function.
- To explore potential immunoregulatory strategies for enhancing bovine mammary gland defense.
Main Methods:
- Mononuclear cells were isolated from blood, lymph node, and mammary tissue of lactating and periparturient cows.
- Cells were incubated with Staphylococcus aureus in the presence or absence of IL-2.
- Antibacterial activity was assessed, and cell populations were analyzed using flow cytometry.
Main Results:
- IL-2 stimulation significantly increased the bactericidal activity of all tested lymphocyte populations.
- Antibacterial effector cells were primarily CD2+ and lacked macrophages.
- Bactericidal activity remained consistent across different cell sources and lactational stages, irrespective of T-lymphocyte subset shifts.
Conclusions:
- Interleukin-2 enhances the antibacterial capacity of bovine lymphocytes, indicating a potential in vivo immune effector function.
- The primary antibacterial effector cells are CD2+ lymphocytes, distinct from macrophages.
- Further research into the specific phenotype and mechanism of these CD2+ cells could lead to novel strategies for combating bovine mastitis.
Abstract:
The antibacterial activity of bovine lymphocytes was evaluated following in vitro stimulation with interleukin-2. Mononuclear cells were isolated from the blood, lymph node, and mammary parenchymal tissue of four lactating and four periparturient dairy cows. These cells were evaluated for antibacterial activity against Staphylococcus aureus following incubation for 48 h with or without interleukin-2. Cultures stimulated with interleukin-2 had higher bactericidal activity of all three isolated cell populations than did unstimulated cultures, regardless of lactational stage. This observation suggests that this effector function may possibly be activated in vivo and may potentially increase mammary gland resistance to bacterial infections during periods of increased susceptibility. Flow cytometric analysis of the cultured cells revealed that antibacterial effector cells were mainly CD2+ and were depleted of macrophages. Despite shifts in CD4+, CD8+, and gamma delta T lymphocytes during the periparturient period, bactericidal activity was similar among the three cell sources. This similarity suggests that these lymphocyte phenotypes might not be directly responsible for this effector function. Identification of the antibacterial effector phenotype and its mechanism of action may lead to immunoregulatory strategies aimed at enhancing this novel bactericidal function.
